(1) Field of the Invention
This invention relates to a method for merging goods and an apparatus for carrying out the method. Particularly, it relates to a method for merging goods and an apparatus therefor, wherein switching time loss for merging goods is reduced and merging capacity is increased by reducing the frequency of switching for merging goods, counting errors are reduced and merging capacity is increased by counting the goods before they are transferred on a storage line (line on which goods are temporarily stored before merged), and merging capacity (number of goods/time) is maintained generally at a constant level irrespective of the sizes of goods by setting a space between adjacent goods generally constant, the goods being conveyed after being merged.
(2) Description of the Prior Art
A conventional method for merging goods and an apparatus therefor are described, for example, in Japanese patent publication No. 58-23294, Japanese patent early laid-open publication No. 51-20358, Japanese patent early laid-open publication No. 51-151954, and Japanese patent early laid-open publication No. 59-69314.
The above publications will now be briefly described. Japanese patent publication No. 58-23294 discloses the art in which in order to obtain a good balancing of the arrangement of goods which are to be transferred to a main stream conveyor from various branch stream conveyors, the goods are carried out starting from those on a downstream side branch stream conveyor and ending with those on an upstream side conveyor, and thereafter goods are carried out starting from those on an upstream side branch stream conveyor and ending to those on a downstream side branch stream conveyor.
Japanese patent early laid-open publication No. 51-20358 discloses the art in which the priority of carrying-out goods (i.e., the order of goods to be carried out) is established according to instructions from a goods carry-out port, a conveying order of rows of goods is established from such established priority regarding the carrying-out of goods and the loading state of a conveyor, and the goods are then forwarded on the conveyor through various goods inlet ports based on such established-conveying order of the rows of goods.
Japanese patent early laid-open publication No. 51-151954 discloses the art in which after it is detected that all goods merged on a main conveyor line have passed the merging point at the most downstream side waiting conveyor line of a plurality of waiting conveyor lines where goods to be conveyed are waiting, the succeeding goods are merged.
Japanese patent early laid-open publication No. 59-69314 discloses the art in which when a stopper opening-and-closing sequence of a subline is built in a memory unit provided with a subline number in the direction of a data inlet/outlet line and with a tact in the address direction, an area of the memory unit is diagonally allocated to form diagonal tacts, the diagonal tacts each necessarily including only a stopper open information "1" of one subline, the stoppers of the remaining sublines all including a close information "0", in this way, the contents of open/close memory of a subline being arranged in the memory unit comprising a shift registor, etc., goods being transferred on a main line by opening or closing the stoppers which are each disposed at an outlet port of each subline according to the stopper open-and-close informations which are arranged as described previously.
However, the above-described conventional methods for merging goods and apparatuses therefor have the following problems.
That is, in the above-described publications, in the case goods are in the front end portion of the storage line for merging goods or merging line, all goods or a predetermined quantity of goods on the storage line are carried out and merged in the predetermined order (carring-out action is not necessarily started after goods have filled the whole space on the storage line along its entire length). Accordingly, the frequency of switching action for merging is large, thus preventing a high merging capacity.
In Japanese patent publication No. 58-23294 and Japanese patent early laid-open publication No. 51-20358, since the goods are counted in the vicinity of the merging portion, the speed for conveying goods at the merging portion is limited depending on the counting capacity. That is, if goods, which are being conveyed at a high speed, are to be counted, there often occur such counting errors as that same goods are counted twice or two goods are counted as one due to swaying (dancing). In the case where the goods are to be counted in the vicinity of the merging portion, incorrectly-counted goods are conveyed to the succeeding line via the merging conveyor line without correcting the counting errors. Therefore, in the case where the succeeding line is, for example, a diverting line, there sometimes occur such instances where goods are forwarded to a wrong assembly/storage line. In Japanese early laid-open publication No. 51-151954 and Japanese early laid-open publication No. 59-69314, goods are carried out one by one (in the case goods are carried out one by one, the loss time for switching goods for merging is large). In addition, there is no description nor suggestion that goods are counted.
Furthermore, none of the above-described publications describe and/or suggest the speed with which goods are carried out from the storage line. Therefore, in the case where goods having various sizes are conveyed at a constant carry-out speed, the conveying spaces between adjacent merged-goods becomes irregular. Therefore, when goods must be supplied to the succeeding line with more than a predetermined space maintained between adjacent goods, the speed for carrying out goods must be set considering the smallest goods. The result is that when large goods are conveyed, a large space more than neccessary is formed between adjacent goods and high merging capacity is unobtainable.